/*
 * Mege sort
 */

#include<stdio.h>

#define MAX 16

int rand(void);
void merge(int arr[], int low, int mid, int high);
void sort(int arr[], int low, int high);

int main(void)
{
    int buf[MAX], i;

    for(i = 0; i < MAX; i++)
    {
        buf[i] = rand();
        printf("%6d", buf[i]);
    }
    printf("\n");

    sort(buf, 0, MAX-1);

    for(i = 0; i < MAX; i++)
    {
        printf("%6d", buf[i]);
    }
    printf("\n");

   return 0;
}

void sort(int arr[], int low, int high)
{
    int mid;

    if(low < high)    // if not one-element array
    {
         mid = (low + high)/2;
         sort(arr, low, mid);
         sort(arr, mid+1, high);
         merge(arr, low, mid, high);
    }
}

void merge(int arr[], int low, int mid, int high)
{
    int i, m, k, l, temp[MAX];

    l = low;
    i = low;
    m = mid + 1;

    while((l <= mid) && (m <= high))
    {
        if(arr[l] <= arr[m])
        {
            temp[i] = arr[l];
            l++;
        }
        else
        {
            temp[i] = arr[m];
            m++;
        }
        i++;
    }

    if(l > mid)
    {
       for(k = m;k <= high;k++)
       {
           temp[i] = arr[k];
           i++;
       }
    }
    else
    {
        for(k = l;k <= mid;k++)
        {
            temp[i] = arr[k];
            i++;
        }
    }
   
    for(k = low;k <= high;k++)
    {
        arr[k] = temp[k];
    }
}